With £300 - £400 to spend, the following might be useful options:
1) Garmin Quest - £350 with a bike mount, but this package only comes with UK mapping:
1a) Garmin Quest EU v8 £300 (latest mapping) No bike mount. Check out the detailed review linked on the page below
2) Garmin Quest2 -out of your budget at £460, but comes with Western Europe mapping (see the link for coverage in each country)
3) GPSMAP 76c - £250 no bike mount supplied, but does have Western Europe Mapping Basemap and CD, although I don't know how many countries worth of mapping could be stored in the relatively small memory which, unlike it's newer 76xxx sister models is not upgradable.
I would want a Touratech bracket for any unit I was using - mainly for rough road/piste isolation from vibrations, but also lockable so it could be left on the bike at fuel stations etc.
With all the units above the displays show 2d mapping, so it's almost like pulling a paper map out of your pocket and seeing where to go - it's quite hard to relate it to the road ahead and may result in you not paying due attention to the road, unless you pull over first of course. Item 3) also has a smaller display.
4) TomTom Rider - £375, UK only mapping, but Europe available as an upgrade. This is a fantastic product to use whilst riding (within the limited map coverage) as it has a 3d display; glance down and you see a simplified representation of the same place you're riding through and can immediately tell where to go at each junction without having to work out how a 2d map relates to your road-view. But it will only tel you your WGS84 datum based grid position (Long &Lat) when you're off map.
I'm afraid this isn't an exhaustive list, have a look at http://www.touratech.de/shop_uk/enter.html
then 'Navigation' to see more options and check that you can get a bike bracket for the one you choose.
The Garmin units alllow you to continue to navigate off-map to waypoints in an 'as the crow flies' manner. They also record a 'track-log', that is a breadcrumb trail of where you've been, so you can retrace your steps, or look at your route on Google Earth when you get home.
With any unit, especially the 'offers' above you should query which version of mapping software is supplied. As well as roads changing each year - bypasses, new motorways, new one way systems etc, the coverage for countries is vastly improved. NB only GB/France/Germany and a couple of other countries have high 90s% road coverage in the electronic mapping, the others are catching up each year.
The most complete European (Western!) mapping above is maybe option 2 - the Quest2, but this doesn't cover the Baltics, the most Eastern it gets is :
"Czech Republic: Prague, Brno, Plzen, Karlovy Vary, Ostrava and Mlada Boleslav
Which presumably means it only covers these towns, not the whole of the countries.
Garmin's current mapping can be reviewed here:
'City Navigator' - http://www.garmin.com/cartography/mapSource/citynavEuro.jsp
'Worldmap' - http://www.garmin.com/cartography/mapSource/WM.jsp
You really need to use the tools to view the map, zoom in & explore - the 'Worldmap' product only shows most of the main roads and gets them to within 1/2 mile or so of their correct position, it doesn't support auto-routing either. In Africa I found it completely missed whole towns, had towns where there were none and gave towns wrong names. So to find an address or navigate without the help of a map it is of very little use.
TomTom's mapping can be reviewed here:
- Actually it seems that there are quite a few W European countries at 99% map coverage now.
Now, if I were planning your trips, I'd probably be dissapointed at the lack of electronic mapping for the Balkans and Russia, sure Garmin's worldmap gives very limited coverage, but it does generally gives the correct positions for towns and when used with a paper map ahead of your trips, you could put a series of waypoints into a GPSR based on the town locations and have a directional arrow display to the next town, along with the town name (I am not sure if cyrillic is supported and if it is could vary by brand & model). This could be useful in my view. You don't need a unit that supports mapping to do this, but maybe the mapping would be helpful through Western Europe anyway.
You can either use the manufacturer's software - Such as Garmin Mapsource Worldmap, or 3rd party software, such as TTQV from Touratech. This can be downloaded for unrestricted trial use for 25 days from http://ttqv.com/main.php?content=21&download=13
Did you pick up a Touratech brochure at HUUK? The description on P140 for TTQV says it can work with Garmin maps & there are many different internet offers for free Garmin maps (I've not seen them, unless they're talking about pirate copies or 3rd party Garmin mapping projects such as tracks4africa) and it will load maps into the Garmin GPS map memory. But I'm sure you would have to buy a license for the map from Garmin to activate it on the GPS. Now they do also sell their own Eastern Europe DVD Routing & Balkan States (P153), Romania, Western CIS etc eMaps. But I think these can only be used on the PC, some can do auto-routing, then the routes can be downloaded to the GPS. I have downloaded the free trial, but have not yet had time to have a play with it with my Garmin Maps (I need to find the time & the CDs).
So I hope there is some useful information here, without too much confusion (I did get side tracked once or twice, so ask if anything is not clear) there are also other suppliers of electronic mapping on the internet with user-created maps, such as the excellent tracks4africa, this has spin-offs such as tracks4australia. I don't know if there are Eastern European/CIS/Asia equivalents. Also check out Google Earth, if you haven't already, this can have enough detail to show towns and roads and gives Long/Lat of the cursor position.
NB another point worth considering is that you are more likely to get a 3d Garmin GPS receiver at an affordable price if you leave your purchase until your 2008 trip.
A GPS76c on offer at £99 (at GPSW.co.uk) plus TTQV at £123 +Touratech Eastern Europe at £40 + RAM mount might be useful to you - but you will need to research it to see if it's what you want first, particularly in respect of the small display and buttons that aren't designed for gloves. At least it gives your current location in many local grid sytems to use with any map (as afaik all the Garmins do).
Hope this helps, ride safely.
PS also see this thread for more detailed information on Garmin map products....